Recently, coral gardening has been gaining attention as an effective tool for reef restoration to enhance natural coral recovery and rehabilitate degraded reefs. Coral gardening is the process of collecting coral biomass (generally by breaking off fragments), growing fragments in a nursery, and outplanting the reared corals on reefs. One study showed 1.4-1.8 times more coral produced from coral gardening than undisturbed control colonies and demonstrated that collection of fragments did not significantly damage the donor.

Watch Christina’s presentation on Acropora, a Caribbean coral that serves as a major reef builder providing essential habitats. Since the 1980’s, Acropora has experienced a 80-90% decline.

Around the world, coral reefs have drastically declined due to coastal development, increased water temperatures and storm frequency, global climate change, disease, pollution, and overfishing. In particular, populations of the threatened staghorn coral (Acropora cervicornis) have declined by up to 95% in the Caribbean. To help combat the continuing decline of staghorn coral and assist in their recovery, the Benthic Ecology Lab at the Rosenstiel School is growing corals at an in-water coral nursery to use in restoration activities. The coral nursery is located just east of Boca Chita Key within Biscayne National Park, about a 45-minute boat ride south from the RSMAS dock.

Staghorn coral reproduces naturally through the process of fragmentation, so we collect small pieces of coral called fragments from wild colonies and place them in a coral nursery. The nursery is constructed of cinderblock platforms with 10 pedestals where coral fragments are secured with underwater epoxy. Once secured in the nursery, staghorn fragments can grow up to 15 cm per year. When the fragments have grown to about 30 cm, they can be fragmented again to create more fragments without needing to collect more from wild colonies.

Currently, there are 542 small staghorn coral colonies at the RSMAS coral nursery totaling over 250 meters of healthy coral tissue. The coral nursery attracts many fish and invertebrate species such as snapper, grunts, urchins, lobster, and squid. SCUBA divers regularly clean the nursery with wire brushes to prevent algae and other encrusting organisms like sponges from overgrowing the corals. This process, known as “coral gardening” produces a sustainable, healthy stock of corals which can be transplanted to local coral reefs to help replenish declining staghorn populations. Corals from the RSMAS coral nursery are planned to be outplanted in Spring 2012.